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    <title>Document</title>
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    <script type="text/javascript">

        // function A() { }
        // A.prototype.n = 1
        // var b = new A()
        // A.prototype = {
        //     n: 2,
        //     m: 3,            
        // }
        // var c = new A()
        // console.log(b.n, b.m, c.n, c.m)//1,undefined,2/3

       
        // function Foo() {
        //     Object.prototype.a = function () {
        //         console.log('可访问a')
        //     }
        // }
        // Function.prototype.b = function () {
        //     console.log('可访问b')
        // }
        // var foo = new Foo()
        // foo.a();//可访问a
        // foo.b();//可访问b
        // Foo.a();//可访问a
        // Foo.b();//可访问b


        var fun = function(){}
        fun.prototype={
            name:'peter',
            age:25
        }
        var a = new fun();
        var b = new fun();
        console.log(a.name,b.name);//peter,peter
        fun.prototype.name = 'jack';
        console.log(a.name,b.name);//jack,jack
        fun.prototype = {};
        fun.prototype.name ='tom';
        console.log(a.name,b.name);//jack,jack
        b.constructor.prototype.name = 'kitty';
        console.log(a.name ,b.name);////jack,jack
    </script>
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